Sealed compressor and refrigeration cycle device

ABSTRACT

According to one embodiment, a sealed compressor is configured to suction a working fluid to a rotary compression mechanism section through a suction pipe extending into an accumulator. The sealed compressor has a relation of Aac/Acy≦4, Vac/Vcy≧20, and As/Acy≧0.12 when an inner diameter cross-sectional area of the accumulator is denoted by Aac (mm 2 ), an inner diameter cross-sectional area of a cylinder chamber is denoted by Acy (mm 2 ), an liquid retaining capacity to an upper end of the suction pipe inside the accumulator is denoted by Vac (cc), a total displacement volume of the rotary compression mechanism section is denoted by Vcy (cc), and a total inner diameter cross-sectional area of an extension portion inside the accumulator of the suction pipe is denoted by As (mm 2 ).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of PCT Application No.PCT/JP2012/062997, filed May 22, 2012 and based upon and claiming thebenefit of priority from Japanese Patent Application No. 2011-128363,filed Jun. 8, 2011, the entire contents of all of which are incorporatedherein by reference.

FIELD

Embodiments described herein relate generally to sealed compressors andrefrigeration cycle devices.

BACKGROUND

In a refrigeration cycle device such as an air conditioner, a techniqueis known in which refrigerant compressed by a sealed compressor passesthrough an outdoor heat exchanger, an expansion device, and an indoorheat exchanger connected to the sealed compressor via a four-way valveas a cycle. The sealed compressor used in the refrigeration cycle deviceincludes a rotary compression mechanism section therein and anaccumulator on the suction side thereof. The accumulator prevents aliquid back. Further, the sealed compressor is configured to change itsrotation speed by an inverter.

In the related art, the sealed compressor was designed to improve itscharacteristics during the operation at a rated rotation speed, forexample, a rotation speed of 60 rps. Then, since the suction loss didnot cause any problem during the operation at the rated rotation speed,the suction loss was not sufficiently considered. However, it is provedthat there is a case in which the suction loss increases and theperformance is largely degraded when the sealed compressor is operatedat the rotation speed other than the rated rotation speed, for example,at a high rotation speed.

BRIEF DESCRIPTION OF THE DRAWINGS

A general architecture that implements the various features of theembodiments will now be described with reference to the drawings. Thedrawings and the associated descriptions are provided to illustrate theembodiments and not to limit the scope of the invention.

FIG. 1 is an explanatory diagram schematically illustrating aconfiguration of a refrigeration cycle device of an embodiment.

FIG. 2 is a cross-sectional view illustrating a configuration of asealed compressor used in the refrigeration cycle device.

FIG. 3 is an explanatory diagram illustrating a relation between asuction loss and an area ratio of a total inner diameter cross-sectionalarea and a cylinder inner diameter cross-sectional area of the sealedcompressor.

FIG. 4 is an explanatory diagram illustrating a relation between anin-pipe flow velocity and the area ratio of the total inner diametercross-sectional area and the cylinder inner diameter cross-sectionalarea of the sealed compressor.

FIG. 5 is an explanatory diagram illustrating a relation between thesuction loss and the area ratio of the total inner diametercross-sectional area and the cylinder inner diameter cross-sectionalarea of the sealed compressor.

DETAILED DESCRIPTION

Various embodiments will be described hereinafter with reference to theaccompanying drawings.

In general, according to one embodiment, a sealed compressor comprises arotary compression mechanism section accommodated in a sealed casing andan accumulator provided outside the sealed casing, the compressorconfigured to suction a working fluid to the rotary compressionmechanism section through at least one suction pipe extending into theaccumulator and connected thereto, wherein the rotary compressionmechanism section comprises at least one cylinder each forming acylinder chamber, and when an inner diameter cross-sectional area of theaccumulator is denoted by Aac (mm²), an inner diameter cross-sectionalarea of one cylinder chamber is denoted by Acy (mm²), a liquid retainingcapacity to an upper end of the suction pipe inside the accumulator isdenoted by Vac (cc), a total displacement volume of the rotarycompression mechanism section is denoted by Vcy (cc), and a total innerdiameter cross-sectional area of an extension portion inside theaccumulator of the suction pipe is denoted by As (mm²), a relation ofAac/Acy≦4, Vac/Vcy≧20, and As/Acy≧0.12 is satisfied.

A refrigeration cycle device 100 that uses a sealed compressor 1according to one embodiment will be described by referring to FIGS. 1 to5.

FIG. 1 is an explanatory diagram schematically illustrating aconfiguration of the refrigeration cycle device 100 according to theembodiment, FIG. 2 is a cross-sectional view illustrating aconfiguration of the sealed compressor 1 and an accumulator 2 used inthe refrigeration cycle device 100, FIG. 3 is an explanatory diagramillustrating a relation between an area ratio As/Acy of a total innerdiameter cross-sectional area As of an extension portion inside theaccumulator of a suction pipe and an inner diameter cross-sectional areaAcy of one cylinder chamber in the sealed compressor 1 and a suctionloss ratio Ws/Wth of suction loss Ws of the extension portion inside theaccumulator of the suction pipe and theoretical work Wth of thecompressor, FIG. 4 is an explanatory diagram illustrating a relationbetween the area ratio As/Acy of the total inner diametercross-sectional area As of the extension portion inside the accumulatorof the suction pipe and the inner diameter cross-sectional area Acy ofone cylinder chamber and in-pipe flow velocity Vs of the extensionportion inside the accumulator of the suction pipe in the sealedcompressor 1, and FIG. 5 is an explanatory diagram illustrating arelation between the area ratio As/Acy and the suction loss ratio Ws/Wthof the sealed compressor 1 during a rated operation and a high-speedoperation.

The refrigeration cycle device 100 is used in an air conditioner.Hereinafter, the refrigeration cycle device 100 will be described as anair conditioner 100.

As illustrated in FIG. 1, the air conditioner 100 comprises: a sealedcompressor 1 comprising an accumulator 2 on a suction side thereof; afour-way valve 101; an outdoor heat exchanger 102 as a heat-source-sideheat exchanger; an expansion device 103; and an indoor heat exchanger104 as a use-side heat exchanger. The air conditioner 100 has aconfiguration in which the sealed compressor 1, the four-way valve 101,the outdoor heat exchanger 102, the expansion device 103, and the indoorheat exchanger 104 communicate with each other as a cycle.

In the air conditioner 100, the four-way valve 101 is connected to asuction side of the accumulator 2 of the sealed compressor 1. Further,in the air conditioner 100, the four-way valve 101 is connected to adischarge side of the sealed compressor 1. In the air conditioner 100,the outdoor heat exchanger 102, the expansion device 103, and the indoorheat exchanger 104 are sequentially connected to the four-way valve 101,and the flow direction of refrigerant discharged from the sealedcompressor 1 is switched when the passageway of the four-way valve 101is switched.

The sealed compressor 1 includes a sealed container 10, a rotarycompression mechanism section 11 provided in the lower portion insidethe sealed container 10, a motor unit 12 provided in the upper portionof the sealed container 10, a refrigerant suction pipe 13 provided inthe sealed container 10, and a refrigerant discharge pipe 14 provided inthe sealed container 10. Further, the sealed compressor 1 includes theaccumulator 2 connected to the suction pipe 13.

The upper portion of the sealed container 10 is provided with an uppercover 10 a which seals the inside of the sealed container 10, and theupper cover 10 a is fixed by welding or the like so as to seal theinside of the sealed container 10 after the rotary compression mechanismsection 11 and the motor unit 12 are accommodated in the sealedcontainer 10.

The rotary compression mechanism section 11 includes a first cylinder21, a second cylinder 22, a rotary shaft 23, a pair of rollers 24, abearing 25, a partition plate 26, and blades.

The first cylinder 21 forms a first cylinder chamber 21 a having acolumnar shape. Further, the first cylinder 21 includes a bladeaccommodation groove communicating with the first cylinder chamber 21 aand a suction port connected to the suction pipe 13 so as to communicatewith the first cylinder chamber 21 a. The blade is accommodated in theblade accommodation groove so as to protrude and retract with respect tothe first cylinder chamber 21 a.

The outer dimension of the first cylinder 21 is slightly smaller thanthe inner diameter of the sealed container 10. The first cylinder 21 isinserted into the sealed container 10, and is positioned and fixed tothe inner peripheral surface of the sealed container 10 by welding fromthe outside of the sealed container 10. Furthermore, the first cylinder21 includes a communication hole 21 b which causes a lower space of thefirst cylinder 21 to communicate with an upper space of the firstcylinder 21 when the first cylinder is fixed to the sealed container 10.

The second cylinder 22 forms a second cylinder chamber 22 a having acolumnar shape. Further, the second cylinder 22 includes a bladeaccommodation groove communicating with the second cylinder chamber 22 aand a suction port connected to the suction pipe 13 so as to communicatewith the second cylinder chamber 22 a. The blade is accommodated in theblade accommodation groove so as to protrude and retract with respect tothe second cylinder chamber 22 a.

The first cylinder 21 and the second cylinder 22 have different outershapes and dimensions. Furthermore, the first cylinder chamber 21 a andthe second cylinder chamber 22 a are set to have the same inner diameterand the same height.

The rotary shaft 23 is inserted through the first cylinder chamber 21 aand the second cylinder chamber 22 a and is pivoted by the bearing 25.The rotary shaft 23 includes crank eccentric portions 28 which arepositioned inside the first cylinder chamber 21 a and the secondcylinder chamber 22 a so as to have, for example, a phase difference ofabout 180°.

The two crank eccentric portions 28 have the same eccentric amount, andthe heights thereof are slightly smaller than those of the firstcylinder chamber 21 a and the second cylinder chamber 22 a.

Rollers 24 respectively engage with the crank eccentric portions 28 soas to be slidable inside the first cylinder chamber 21 a and the secondcylinder chamber 22 a and to be slidable on the end of the blade. Theheights of the rollers 24 are substantially equal to the heights of thefirst cylinder chamber 21 a and the second cylinder chamber 22 a.

Since the pair of rollers 24 are provided at the crank eccentricportions 28 disposed with a phase difference therebetween, the rollershave a phase difference of about 180°. The rollers 24 eccentricallyrotate inside the first and second cylinder chambers 21 a and 22 a.Since the first and second cylinder chambers 21 a and 22 a have the sameinner diameter and the same height and the two crank eccentric portions28 and 28 have the same eccentric amount, the first and second cylinders21 and 22 have the same displacement volume.

The bearing 25 includes a primary bearing 31 provided in an uppersurface portion of the first cylinder 21 covering the upper side of thefirst cylinder chamber 21 a and a secondary bearing 32 provided in alower surface portion of the second cylinder 22 covering the lower sideof the second cylinder chamber 22 a. The bearing 25 is formed so thatthe rotary shaft 23 is pivoted by the primary bearing 31 and thesecondary bearing 32.

The primary bearing 31 forms the upper surface of the first cylinderchamber 21 a, and the roller 24 slides on the upper surface. The primarybearing 31 is equipped with a first valve cover 33 which covers theupper side of the primary bearing 31. Further, the primary bearing 31includes a first discharge hole 34 which guides the refrigerant from thefirst cylinder chamber 21 a to the first valve cover 33 and a firstopen/close valve 35 which opens and closes the first discharge hole 34.

The secondary bearing 32 forms the lower surface of the second cylinderchamber 22 a, and the roller 24 slides on the lower surface. Thesecondary bearing 32 is equipped with a second valve cover 36 whichcovers the lower side of the secondary bearing 32. Further, thesecondary bearing 32 includes a second discharge hole 37 which guidesthe refrigerant from the second cylinder chamber 22 a to the secondvalve cover 36 and a second open/close valve 38 which opens and closesthe second discharge hole 37.

Furthermore, the first cylinder 21, the second cylinder 22, thepartition plate 26, the primary bearing 31, the secondary bearing 32,the first valve cover 33, and the second valve cover 36 are integrallycoupled to one another by a bolt B and the like, and the coupledcomponents are fixed to the sealed container 10 via the first cylinder21.

The partition plate 26 has an outer diameter larger than the innerdiameters of the first cylinder chamber 21 a and the second cylinderchamber 22 a and smaller than the outer dimensions of the first cylinder21 and the second cylinder 22. The partition plate 26 is disposed so asto cover the first cylinder chamber 21 a and the second cylinder chamber22 a.

The blade is formed so that its height is substantially equal to each ofthe heights of the first and second cylinder chambers 21 a and 22 a. Theblade is formed so that its front end has, for example, asemi-cylindrical shape. For example, when a back pressure is applied tothe back surface of the blade, the blade is pressed toward the roller 24by the back pressure, and the front end of the blade comes intoline-contact with the outer peripheral surface of the roller 24regardless of the rotation angle of the roller 24.

The blade accommodation grooves are respectively formed in the first andsecond cylinders 21 and 22 so that the blades partition between thesuction ports and the first and second discharge ports 34 and 37. Whenthe blades comes into contact with the rollers 24, the first and secondcylinder chambers 21 a and 22 a are defined as the suction chambers andthe compression chambers.

The motor unit 12 includes a stator 51 fixed to the inner surface of thesealed container 10 and a rotor 52 disposed inside the stator 51 with apredetermined gap therebetween. The rotor 52 is fixed to the rotaryshaft 23. The motor unit 12 is connected to, for example, an inverterthat changes the operation frequency. Furthermore, the inverter iselectrically connected to a control unit that controls the inverter, andchanges the rotation speed of the rotary shaft 23 to an arbitraryrotation speed if necessary.

Two suction pipes 13 are respectively connected to the suction ports ofthe first cylinder 21 and the second cylinder 22. Further, each suctionpipe 13 is bent upward by about 90° at the halfway portion protrudingfrom the sealed container 10 so as to extend into the accumulator 2, andits end is disposed at a predetermined height of the accumulator 2.Furthermore, the height of the end of the suction pipe 13 extending intothe accumulator 2 is appropriately set if necessary since the capacityfor the liquid refrigerant and lubricating oil storable inside theaccumulator 2 changes by the height.

Further, the suction pipe 13 includes an oil return hole 13 a providedat a predetermined position in the height direction from the bottomsurface of the accumulator 2 in the portion extending into theaccumulator 2. Furthermore, the oil return hole 13 a may be formed so asto supply the lubricating oil accumulated at the lower side inside theaccumulator 2 to the first cylinder chamber 21 a and the second cylinderchamber 22 a along with the gas refrigerant, and the height of the oilreturn hole 13 a is appropriately set depending on the dimension or thecapacity of the accumulator 2.

The discharge pipe 14 is connected to the upper end of the sealedcontainer 10, that is, the upper cover 10 a. The discharge pipe 14 isconnected to the four-way valve 101.

The accumulator 2 includes a cylindrical container 61 of which both endsare blocked and a gas/liquid separation unit 62 provided inside thecontainer 61. In the accumulator 2, the suction pipe 13 is inserted intothe container 61 from the lower end of the container 61, the suctionpipe 13 extends to the position right below the gas/liquid separationunit 62, and the upper end of the container 61 is connected with areturn pipe 63 through which the refrigerant returns. Furthermore, thereturn pipe 63 is connected to the four-way valve 101.

The gas/liquid separation unit 62 is a refrigerant guide unit thatprevents the refrigerant returned from the return pipe 63 from directlyentering the suction pipes 13 and 13 right below the gas/liquidseparation unit 62. That is, the gas/liquid separation unit 62 is formedso that the refrigerant as the gas/liquid mixture returned from thereturn pipe 63 may collide with the gas/liquid separation unit 62 andthe colliding refrigerant as the gas/liquid mixture may be guided towardthe inner peripheral surface of the container 61.

The accumulator 2 is a so-called a gas/liquid separator capable ofstoring the liquid refrigerant and the lubricating oil at the lower sideof the container 61 by the gas/liquid separation unit 62 and supplyingthe gas refrigerant from the suction pipe 13.

Further, in the sealed compressor 1, as illustrated in FIG. 2, when theinner diameter cross-sectional area of the container 61 of theaccumulator 2 is denoted by Aac (mm²), the inner diametercross-sectional area of each of the first and second cylinder chambers21 a and 22 a (the inner diameter cross-sectional area of one cylinderchamber) is denoted by Acy (mm²), the total inner diametercross-sectional area of extension portions inside the accumulator of thesuction pipes 13 and 13 (the sum of the inner diameter cross-sectionalareas of two suction pipes) is denoted by As (mm²), the totaldisplacement volume of the rotary compression mechanism section 11 ofthe sealed compressor 1 (the sum of the displacement volumes of thefirst and second cylinders 21 and 22) is denoted by Vcy (cc), the liquidretaining capacity from the bottom surface of the container 61 to theupper end of the suction pipe 13 of the accumulator 2 is denoted by Vac(cc), the inner diameter of each of the first and second cylinderchambers 21 a and 22 a (the inner diameter of one cylinder chamber) isdenoted by φDcy (mm), the axial distance between the upper surface ofthe first cylinder 21 and the lower surface of the second cylinder 22 isdenoted by L (mm), the distance between the axial center of the firstcylinder 21 and the axial center of the second cylinder 22 is denoted byLc (mm), and the distance between the axial centers of the connectingportions of two suction pipes 13 and 13 with respect to the firstcylinder 21 and the second cylinder 22 is denoted by Lp (mm), therespective dimensions of the sealed compressor 1 are set so as tosatisfy the relation of

Aac/Acy≦4,

0.12 As/Acy≦0.25,

Vac/Vcy≧20,

0.9≦L/Dcy≦1.1, and

Lp>Lc.

Furthermore, the inner diameter cross-sectional area Aac of theaccumulator 2 indicates the opening area of the body of the container 61of the accumulator 2. The total inner diameter cross-sectional area Asof extension portions inside the accumulator of the suction pipes 13 and13 indicates the sum of the opening areas of two suction pipes 13extending into the accumulator 2. Further, the total displacement volumeVcy of the first and second cylinders 21 and 22 indicates the sum of thedisplacement volume of the first cylinder 21 as the volume between theinner peripheral surface of the first cylinder chamber 21 a and theouter peripheral surface of the roller 24 and the displacement volume ofthe second cylinder 22 as the volume between the inner peripheralsurface of the second cylinder chamber 22 a and the outer peripheralsurface of the roller 24.

The liquid retaining capacity Vac of the accumulator 2 indicates thecapacity in which the liquid refrigerant and the lubricating oil may bestored inside the accumulator 2 when the accumulator performs thegas/liquid separation and specifically, the volume reaching the waterlevel at which the liquid refrigerant and the lubricating oil do notenter the suction pipes 13 and 13 inside the accumulator 2 becomes theliquid retaining capacity.

In the air conditioner 100 that uses the sealed compressor 1 with such aconfiguration, when power is first supplied to the motor unit 12 of thesealed compressor 1 from a driving device such as an inverter, the rotor52 rotates, and hence the rotary shaft 23 fixed to the rotor 52 rotates.Due to the rotation of the rotary shaft 23, the crank eccentric portions28 and 28 and the rollers 24 and 24 eccentrically rotate. By therotational sliding actions of the rollers 24 and 24, the refrigerantsuctioned into the first cylinder chamber 21 a and the second cylinderchamber 22 a is compressed.

When the rollers 24 and 24 move to a predetermined position, the firstand second open/close valves 35 and 38 are opened, and the compressedrefrigerant is discharged from the first discharge hole 34 and thesecond discharge hole 37 into the sealed container 10 through the firstvalve cover 33 and the second valve cover 36. The refrigerant which flowinto the sealed container 10 moves to the four-way valve 101 through thedischarge pipe 14.

Here, the four-way valve 101 connects the secondary side of the sealedcompressor 1 to the outdoor heat exchanger 102 during the coolingoperation of the air conditioner 100. As indicated by the solid arrow Cof FIG. 1, the refrigerant compressed by the sealed compressor 1 passesthrough the outdoor heat exchanger 102, and exchanges heat with theoutdoor air so as to be condensed. Subsequently, the condensedrefrigerant passes through the indoor heat exchanger 104 through theexpansion device 103, exchanges heat with the indoor air, evaporates,and cools the indoor air.

The refrigerant which passes through the indoor heat exchanger 104passes through the four-way valve 101 and moves to the accumulator 2. Inthe refrigerant which moves into the accumulator 2, the liquidrefrigerant and the lubricating oil are stored in the accumulator 2 bythe gas/liquid separation unit 62, and the gas refrigerant are suctionedfrom the suction pipes 13 into the sealed compressor 1. Further, at thistime, the stored lubricating oil is suctioned from the oil return hole13 a and is suctioned into the first cylinder chamber 21 a and thesecond cylinder chamber 22 a along with the gas refrigerant. Byrepeating these operations, the air conditioner 100 performs a heatexchange operation as a cooling operation.

Furthermore, in the heating operation of the air conditioner 100, thefour-way valve 101 connects the secondary side of the sealed compressor1 to the indoor heat exchanger 104. As indicated by the dashed arrow Hof FIG. 1, the refrigerant compressed by the sealed compressor 1 passesthrough the indoor heat exchanger 104 and exchanges heat with the indoorair to be condensed. The condensed refrigerant passes through theoutdoor heat exchanger 102 through the expansion device 103, andexchanges heat with the outdoor air in the outdoor heat exchanger 102 toevaporate. The evaporating refrigerant is separated into gas and liquidthrough the four-way valve 101 and the accumulator 2, and is suctionedby the sealed compressor 1. By repeating these operations, the airconditioner 100 performs a heat exchange operation as a heatingoperation.

Next, the basis of the setting of the respective dimensions of thesealed compressor 1 according to the embodiment will be described indetail by referring to FIGS. 3 to 5.

In the sealed compressor 1 using the rollers 24, when the ratio Aac/Acybetween the inner diameter cross-sectional area Aac (mm²) of thecontainer 61 of the accumulator 2 and the inner diameter cross-sectionalarea Acy (mm²) of each of the first and second cylinder chambers 21 aand 22 a (the inner diameter cross-sectional area of one cylinderchamber) becomes larger than 4, the inner diameter of the accumulator 2increases, the entire sealed compressor 1 increases in size, the weightbalance becomes poor, and the installation property is degraded. On thecontrary, in the sealed compressor 1 of the embodiment, since the ratioAac/Acy is set to 4 or less, the accumulator and the entire sealedcompressor 1 decrease in size and the weight balance and theinstallation property may be improved.

Further, when the ratio Aac/Acy is simply set to 4 or less, the innerdiameter of the accumulator 2 decreases, and hence there is a concernthat the gas/liquid separation function may be degraded. For thisreason, as a result of various experiments, when the ratio Vac/Vcybetween the liquid retaining capacity Vac from the lower surface of thecontainer 61 to the upper end of the suction pipe 13 of the accumulator2 and the total displacement volume Vcy of the rotary compressionmechanism section 11 (the sum of the displacement volumes of the firstand second cylinders 21 and 22) is set to 20 or more, a sufficientliquid retaining capacity may be ensured, and the liquid back may beprevented.

Further, FIG. 3 illustrates the relation between the ratio As/Acybetween the total inner diameter cross-sectional area As of extensionportions inside the accumulator of the suction pipes 13 and 13 (the sumof the inner diameter cross-sectional areas of two suction pipes) andthe inner diameter cross-sectional area Acy (mm²) of each of the firstand second cylinder chambers 21 a and 22 a (the inner diametercross-sectional area of one cylinder chamber) and the ratio Ws/Wthbetween the suction loss Ws of extension portions inside the accumulatorof the suction pipes 13 and 13 and the theoretical work Wth of thecompressor. That is, in FIG. 3, the horizontal axis indicates the ratioAs/Acy, and the vertical axis indicates the ratio Ws/Wth. From FIG. 3,it is understood that the ratio Ws/Wth increases as the ratio As/Acydecreases and the ratio Ws/Wth, that is, the ratio of the suction losswith respect to the theoretical work abruptly increases particularlywhen the ratio As/Acy becomes smaller than 0.12.

As described above, when the ratio As/Acy is set to 0.12 or more, thesuction loss Ws of the suction pipes 13 and 13 inside the accumulator 2with respect to the theoretical work Wth of the compressor may be set tosubstantially 2% or less as illustrated in FIG. 3. Here, the theoreticalwork Wth of the compressor indicates the theoretical work which isderived by the design calculation of the sealed compressor 1.

Furthermore, FIG. 3 illustrates the measurement characteristics of fourtypes of sealed compressors by preparing the sealed compressor in whichthe heights of the first cylinder 21 and the second cylinder 22 arerespectively set to 18 mm using the configuration of two cylinders ofthe first cylinder 21 and the second cylinder 22 of the embodiment, thesealed compressor in which the heights of the first cylinder 21 and thesecond cylinder 22 are respectively set to 22 mm using theabove-described configuration, the single cylinder type sealedcompressor with one cylinder in which the height of the cylinder is setto 20 mm, and the single cylinder type sealed compressor in which theheight of the cylinder is set to 25 mm. As illustrated in FIG. 3, thecharacteristics of four types of the sealed compressors substantiallyoverlap one another along the same curve. In the four types of thesealed compressors, the inner diameters of the respective cylinderchambers are set to 43 mm and the characteristics are measured byadjusting the operation rotation speed so that the cooling abilitybecomes 15 kw using the refrigerant of R410A.

As apparent from FIG. 3, since the relation of As/Acy≦0.12 is set, thesuction loss ratio Ws/Wth (%) may be reduced regardless of the number ofthe cylinders or the volume thereof, and an abrupt increase in thesuction loss may be prevented.

FIG. 4 is an explanatory diagram illustrating a relation between thearea ratio As/Acy of the total inner diameter cross-sectional area As ofthe extension portion inside the accumulator of the suction pipe of thesealed compressor 1 and the inner diameter cross-sectional area Acy ofone cylinder chamber and the in-pipe flow velocity Vs(m/s) of theextension portion inside the accumulator of the suction pipe, where thehorizontal axis indicates the area ratio As/Acy and the vertical axisindicates the in-pipe flow velocity Vs(m/s).

In a case where the ratio As/Acy is set to 0.12 or more, as illustratedin FIG. 4, there is a tendency that the in-pipe flow velocity Vs (m/s)of the suction pipe 13 inside the accumulator 2 decreases as the ratioAs/Acy increases even when one cylinder or two cylinders are used.

The suction pipe 13 inside the accumulator 2 is provided with the oilreturn hole 13 a that returns the lubricating oil accumulated in theaccumulator 2, and the lubricating oil is returned from the oil returnhole 13 a to the first cylinder chamber 21 a and the second cylinderchamber 22 a. Here, when the in-pipe flow velocity Vs decreases, thereis a concern that the oil may not be sufficiently returned from the oilreturn hole 13 a.

However, as illustrated in FIG. 4, when the relation of As/Acy≦0.25 issatisfied, the in-pipe flow velocity Vs may be maintained at 1 (m/s) ormore, and the oil may be reliably returned by the oil return hole 13 a.

FIG. 5 is an explanatory diagram illustrating a relation between thearea ratio As/Acy and the ratio Ws/Wth of the suction loss Ws and thetheoretical work Wth of the compressor in the sealed compressor 1 at therated rotation speed (60 rps) and the high rotation speed (125 rps).

As apparent from FIG. 5, when the relation of 0.12≦As/Acy≦0.25 andVac/Vcy≧20 is satisfied, the suction loss ratio Ws/Wth (%) may bereduced at not only the rated rotation speed (60 rps) but also the highrotation speed (125 rps), and an increase in the suction loss may beprevented.

Further, when the ratio L/Dcy of the axial distance L (mm) between theupper surface of the first cylinder 21 and the lower surface of thesecond cylinder 22 and the inner diameter φDcy (mm) of each of the firstand second cylinders 21 and 22 (the inner diameter of one cylinderchamber) is set to be smaller than 0.9, the heights (thicknesses) of thefirst and second cylinders 21 and 22 decrease, and the suction portsconnecting the suction pipes 13 and 13 also decrease in size, so thatthe suction loss increases. Meanwhile, when the ratio L/Dcy becomeslarger than 1.1, the distance between the bearings increases, and therotary shaft is bent by the compression load, so that the performance isdegraded.

On the contrary, when the relation of 0.9≦L/Dcy≦1.1 is satisfied, thelarge suction ports of the first cylinder 21 and the second cylinder 22may be ensured, and an increase in the distance between the bearings maybe suppressed, so that degradation in performance may be prevented.

Further, when the relation of the distance Lc (mm) between the axialcenter of the first cylinder 21 and the axial center of the secondcylinder 22 and the distance Lp (mm) between the axial centers of theconnecting portions of two suction pipes 13 and 13 with respect to thefirst cylinder 21 and the second cylinder 22 is set as Lp>Lc, thedistance Lp between the axial centers of the suction pipes 13 and 13 maybe increased. That is, when the suction pipes 13 and 13 are connected tothe sealed container 10, the member connecting the suction pipes 13 and13 is connected to the sealed container 10 by welding. For this reason,when the distance Lp between the axial centers of the suction pipes 13and 13 is set to a large value as possible, degradation in strengthcaused by welding may be prevented.

As described above, according to the air conditioner 100 that uses thesealed compressor 1 of the embodiment, since the above-describedconfiguration is employed, even when the sealed compressor 1 is operatedin a high-speed rotation state, an abrupt increase in the suction lossmay be prevented, and degradation in suction loss may be reduced.Further, according to the air conditioner 100 that uses the sealedcompressor 1, the oil is reliably returned, and hence the reliabilitymay be improved.

Furthermore, the invention is not limited to the refrigeration cycledevice 100 that uses the sealed compressor 1 of the embodiment. In thesealed compressor 1 of the above-described embodiment, a configurationhas been described in which two cylinders, that is, the first cylinder21 and the second cylinder 22 are used as the cylinders, but theinvention is not limited thereto. In the relation of Aac/Acy≦4,0.12≦As/Acy≦0.25, and Vac/Vcy≧20, the number of cylinders may be one orthree or more.

With such a configuration, as illustrated in FIGS. 3 and 4, even in onecylinder, the suction loss may be reduced and the in-pipe flow velocityVs of the suction pipe 13 for returning the oil may be obtained as inthe sealed compressor 1 of the embodiment using two cylinders. Further,the same effect may be obtained even in three cylinders.

Further, in the above-described example, the refrigeration cycle device100 has been described as the air conditioner 100 with a configurationhaving the four-way valve 101, but the invention is not limited thereto.For example, the refrigeration cycle device 100 may also be arefrigeration cycle device that performs only a heating operation or acooling operation without the four-way valve 101 or a refrigerationcycle device other than the air conditioner.

Moreover, in the above-described example, the sealed compressor 1 hasbeen described using a configuration in which the roller 24 and theblade are separately provided, but the invention is not limited thereto.For example, even in a swing type sealed compressor in which a rollerand a blade are integrally provided, the same effect may be obtained.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. A sealed compressor comprising a rotarycompression mechanism section accommodated in a sealed casing and anaccumulator provided outside the sealed casing, the compressorconfigured to suction a working fluid to the rotary compressionmechanism section through at least one suction pipe extending into theaccumulator and connected thereto, wherein the rotary compressionmechanism section comprises at least one cylinder each forming acylinder chamber, and when an inner diameter cross-sectional area of theaccumulator is denoted by Aac (mm²), an inner diameter cross-sectionalarea of one cylinder chamber is denoted by Acy (mm²), a liquid retainingcapacity to an upper end of the suction pipe inside the accumulator isdenoted by Vac (cc), a total displacement volume of the rotarycompression mechanism section is denoted by Vcy (cc), and a total innerdiameter cross-sectional area of an extension portion inside theaccumulator of the suction pipe is denoted by As (mm²), a relation ofAac/Acy ≦4, Vac/Vcy≧20, and As/Acy≧0.12 is satisfied.
 2. The sealedcompressor of claim 1, wherein the inner diameter cross-sectional areaAcy (mm²) of one cylinder chamber and the total inner diametercross-sectional area As (mm²) of the extension portion inside theaccumulator of the suction pipe have a relation of As/Acy 0.25.
 3. Thesealed compressor of claim 1, wherein the rotary compression mechanismsection comprises two cylinders provided with a partition plateinterposed therebetween, and when an inner diameter of one cylinderchamber is denoted by Dcy (mm) and a distance between end surfaces ofsaid two cylinders opposite to the partition plate is denoted by L (mm),a relation of 0.9≦L/Dcy≦1.1 is satisfied.
 4. The sealed compressor ofclaim 1, wherein the rotary compression mechanism section comprises twocylinders provided with a partition plate interposed therebetween andtwo suction pipes connecting the respective cylinders to theaccumulator, and when a distance between axial centers of the respectivecylinders is denoted by Lc (mm) and a distance between axial centers ofconnecting portions of the two suction pipes with the respectivecylinders is denoted by Lp (mm), a relation of Lp>Lc is satisfied.
 5. Arefrigeration cycle device comprising: the sealed compressor of claim 1;a condenser connected to the sealed compressor; an expansion deviceconnected to the condenser; and an evaporator connected to the expansiondevice.